In the wake of the 2014 JO25 asteroid that will approach Earth next week and is expected to fly past our home planet as close as 1.1 million miles away — or 4.6 times the distance from us to the moon — astronomers are weighing the possibility and outcome of a potential critical collision in the future.
The April 19 event marks the asteroid's closest fly-by in at least 400 years, and its calculated trajectory poses no threat of the celestial body colliding with our planet.
Although we are not in any immediate danger, researchers are wondering what would happen if a large-sized asteroid not only flew close to Earth but also actually crashed into the planet's surface.
Small Asteroids Are Stopped By Earth's Atmosphere
The majority of asteroids in our solar system fly in a simple circular orbit between Mars and Jupiter. Occasionally, their path is disturbed either by each other or more frequently by Jupiter's activity, sending them on trajectories that cross that of Mars or even Earth.
Thousands of minuscule debris particles rain down on our planet every day, but the Earth's surface is shielded from any minor impact thanks to air friction. In fact, most asteroids up to 10 meters (or around 33 feet) in diameter are destroyed upon contact with the Earth's atmosphere.
On rare occasions, some asteroid fragments reach the ground, accounting for damaged property. Such was the case of the 27-pound stony meteorite that fell in New York in 1992, jabbing a hole in a parked car.
According to NASA, 33-feet celestial bodies falling from the sky typically have "the kinetic energy of about five nuclear warheads of the size dropped on Hiroshima." This means the created shock wave can do sizeable damage even if only small fragments reach the ground.
In the case of same-sized iron meteoroids, even more fragments are likely to survive the atmospheric contact and land on the surface. The effect of larger pieces falling on the ground would be equivalent to "having a car suddenly drop in at supersonic speeds," NASA states.
This happens almost once every ten years, but the events are seldom recorded since they usually occur at sea or in remote, unpopulated areas like Antarctica.
Big Asteroids Threaten Us Once In A Million Years
Things begin to change when one considers a potential collision with a higher-class asteroid. Once or twice in 1,000 years, a celestial with a 100-meter diameters (or about 330 feet) falls on Earth with the potential to create serious damage.
NASA cites the famous Tunguska (Russia) event in 1908, as well as the asteroid impact in northern Arizona, which left behind a 4,000 feet wide crater — made by a nickel-iron meteorite with a presumed diameter of slightly less than 200 feet.
The chances of an even higher-class asteroid or comet hitting Earth are once in a million years. The most notable example is the 15-miles-wide Ries Crater in Bavaria, which harbors the city of Nordlingen in its center.
This crater was created 15 million years ago, when a 5,000-feet celestial body crashed on our planet's surface. By comparison, the asteroid that is expected to fly past us on April 19 is only 2,000 feet in size.
The largest crater ever discovered is the one at Chicxulub, Mexico, produce by a massive celestial body which brought forth the dinosaur extinction. This type of collision is likely to happen once every 50 to 100 million years — the Chicxulub crater is 65 million years old.
33,000-Feet Asteroid: What Are The Chances?
Researchers at NASA Ames Research Center are monitoring the activity of large-sized asteroids and investigating the likelihood of one of them hitting Earth.
Their estimates indicate the presence of 2,100 asteroids wider than 3,300 feet and suggest there may be up to 320,000 other asteroids in the solar system with a diameter exceeding 330 feet — like the ones that caused the Tunguska and Arizona craters.
"An impact by one of these larger meteors in the wrong place would be a catastrophe, but it would not threaten civilization," reports NASA.
In the even an asteroid wider than 1 or 2 kilometers (3,300 to 6,560 feet) collided with Earth, it could potentially create a worldwide calamity. Impact with such a large-scale body could deteriorate the global climate and place the entire population of the planet in jeopardy. Widespread crop failure would ensue, as well as loss of life. The risk of such a catastrophic event comes around a few times every million years.
Mass extinction is a possibility only if our planet collides with an even larger object, five to 10 times this size. A 33,000-feet asteroid crashing down on us would vaporize "a large amount of the Earth's crust, creating a crater more than one hundred kilometers across," reports Cornell University.
As per the scenario the university's astronomer team imagines, the displaced rocks would be projected into the atmosphere, heating it up, triggering forest fires, and blocking the sunlight.
In the absence of light, Earth's vegetation would fade, leading to the demise of many animal species — including humanity, which would succumb "either in the initial catastrophe, or in the ensuing years due to lack of food and the general devastation of the environment."
